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Carpal tunnel syndrome - with inverted notch sign

Case contributed by Maulik S Patel
Diagnosis almost certain

Presentation

Tingling in fingers for the last few weeks.

Patient Data

Age: about 40 - 45 yrs
Gender: Female

There is the bifurcation of the median nerve proximal to the carpal tunnel. It is a normal variant and known as a bifid median nerve. There is no associated persistent median artery.

Combined Cross-sectional area of two branches -   normal combined up to 11 mm2

Proximal to tunnel - ulnar division - 3 mm2     + radial division - 3 mm2  - Total 6 mm2

Distal to tunnel     - ulnar division - 8 mm2      + radial division - 6 mm2  - Total 14 mm2

Edema followed by tapering distally to the carpal tunnel involves both ulnar and radial divisions which is known as an inverted notch sign.

No intratunnel mass lesion/ flexor tenosynovitis.

Case Discussion

Median nerve edema followed by tapering distally to tunnel involving both ulnar and radial divisions which is known as an inverted notch sign. Findings favor carpal tunnel syndrome.

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